Typically, my wipers stopped working as I was driving during a downpour. At the same time my heater blower stopped and the handbrake light came on. There may have been other symptoms but these were the only ones I noted. It was a simple case of one of the relays coming loose in the fuse box. With the heater blower switched on (engine off), I simply pushed each one until the heater started. It appeared to be relay 18. This could have led to a costly check at a garage.